The present invention disclosed herein relates to a cell searcher for handover of a mobile terminal and a neighbor cell searching method thereof.
In a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system, a base station cannot receive information about a neighbor cell unlike a typical communication system. Accordingly, a mobile terminal cannot receive neighbor cell information from the base station. Accordingly, the mobile terminal requires high detection probability for neighbor cells and real-time processing for searching neighbor cells, in order to achieve fast handover.
The mobile terminal may acquire symbol synchronization by using a Primary Synchronization Signal (PSS). Additionally, the mobile terminal may detect Secondary Synchronization Signal (SSS) after the acquiring of the PSS. The mobile terminal may acquire a cell identifier (cell ID), a CP type, and wireless frame synchronization acquisition by using the obtained SSS. Therefore, when the mobile terminal is handed over to a neighbor cell, it needs to estimate information about neighbor cells by using the PSS and SSS.
The 3GPP LTE system may generate 504 cell IDs by using 3 PSS symbols and 168 SSS symbols. The 3 PSS codes increase presence probability of a neighbor cell having the same PSS code around a specific cell. Therefore, if the PSSs of a home cell and a neighbor cell are the same, a channel coefficient value greatly serves due to the PS of a home cell, so that the detection probability of SSS is reduced in a mobile terminal or the neighbor cell detection probability is reduced since the PSS symbol information of a home cell is reflected on the output symbol timing of a PS code detector.